Condensation in furnaces

[CincyHVAC]

@ Randomnick.........

Have you considered using a condensate pump and route the discharge line to a laundry basin? It would eliminate the need to expose to freezing outdoor temps.

[RandomNick]

Thanks for the replies. Good point about local code... I shouldn't just assume that what they (should have) checked/accepted when these were built is the same as is required now.

There are no nearby drains of any sort. Reaching one would require going up into the unconditioned attic, over, then down.

[hydronicsman]

Other guys may differ but I have used common drains for the furnace and the A/C condensates in attic jobs.

The key is where is it terminating? One gut job enabled me to run the drain interior to the point of termination, where I then angled it at a 45 degree angle to help keep icicles from happening. I also have the term at a place where it can be seen and accessed if that did happen. So far, no probs, and it's been a number of years. The furnace condensate trap and piping exposed in the attic gets self regulating heat tape and tight insulation.

I'm doing a 95%er in an attic now. Seperate drain lines. I cannot run a common line to outside because of the probability of freezing in the exposed drain that runs down the side of the house. That would be a disaster. Again, the exposed furnace trap/drain piping in the attic is heat taped and insulated and the run is as short as possible before submerging into ceiling insulation/living space.

I found a way to get the furnace condensate drain to the basement. There, I will send it through a neutralizer and then pump the water into a laundry standpipe so we don't eat up copper or CI soil lines and kill good bacteria in the septic.

I didn't want to drain the A/C on this line because it would needlessly run through the neutralizer and fill up the septic for no reason.

I would NEVER put a condensate pump in an attic. I'm going to find a way to ground, period.

You have to get creative sometimes..

[Hvacsalesstar]

For the furnace exhaust to exit out of the drain area there would have to be a negative pressure in the area of the furnace. If the there is no negative pressure and the ventor fan is working, the exhust would be exisiting correctly(assuming the venting is not obstructed) to the outdoors.
As the exhaust cools down it forms a liquid which would drain out to the drain. I agree not to add a pump in the attic.
Cheers

[RandomNick]

The last two posts have me confused. I imagine two freezing concerns:

1. Condensate freezing inside the drain line, when that drain line is exposed to freezing temperatures. This would seem to apply if the drain line runs outside the house OR if the drain line runs in an unconditioned attic. Both could be heat taped.
   
   Based on my talks with contractors, they seemed more concerned about one that runs outside. In fact, the two that want to go up into my attic and dump into the sewer vent felt that they wouldn't have to heat tape that line if they laid the line on top of existing insulation and put more insulation on top. The suggestion being, that enough warmth (from the home beneath and/or condensate fluid) would be in that insulation sandwich to keep that line from freezing. I don't know how well a condensate pump would evacuate such an "up and over line". I can only assume that such a line would not be thoroughly evacuated and thus there would be condensate in the line to freeze.
   
   
2. Blockage of a drain line that simply exists the house and dumps condensate on the ground. Said blockage could result from frozen condensate or snow/ice buildup in the area.
   
   I expect there is only so much one could to do try to prevent that. Through heat tape, for example, one could assure that the condensate remains warm. However, once it is outdoors you have no control over it. A buildup would seem possible and thus have to be watched for. Perhaps this is why some preferred to go up into the attic and into the sewer vent... they could eliminate this uncontrollable variable.
   
   Rereading the bit about conditioning the effluent, I wonder if dumping acidic condensate into a public sewer line sometimes causes problems.

In the last two messages there appears to be one "heat taped line in attic is OK" and two "no condensate pumps in attic". I don't understand why a heat taped line in the attic would be considered OK while a (heat taped) condensate pump in the attic would be considered a no go(?).

[fearlessfurnace]

yeah freezing outside or in unconditioned space is the consern..hate to trust heat tape or "heat leakage". various safty shutoffs are availible. also something springing a leak in the attic is unpleasant to say the least.